CIA cryptonyms are code words seen in declassified documents of the U.S. Central Intelligence Agency. There has been much speculation as to the meaning of these.

Each CIA cryptonym in these documents contains a two character prefix called a digraph, which designates a geographical or functional area. The rest is either an arbitrary dictionary word, or occasionally the digraph and the cryptonym combine to form a dictionary word (e.g.: AEROPLANE). Certain digraphs were changed at times, for example the digraph for the Soviet Union changed at least twice.

Partial list of digraphs and probable definitions

AE: Soviet Union

AM: Cuba

BE: Poland

CK: Soviet Union

DI: Czechoslovakia

DM: Yugoslavia

DN: South Korea

ES: Guatemala

GT: Soviet Union

IA: Angola

KU: Part of CIA

MH: Worldwide operation

MK: Projects sponsored by the CIA's Technical Services Division

OD: Other Department

PB: President Board

SD: Iran

SM: United Kingdom

TU: South Vietnam

ZR: Normally prefixes the cryptonym for an intelligence intercept
program. Seems to go with Staff D ops, Staff D being the group that
worked directly with the NSA. Staff D was where ZR/RIFLE, a Castro
assassination plot, was buried.